sq7

The DISTINCT keyword allows you to find unique values in a column.

Once a table starts getting a lot of data in it, some columns will contain duplicate values.

For example, many Individuals share first names and surnames. Most of the time this isn't a problem. But sometimes you will want to find out how many unique values there are in a column. To do this you can use the DISTINCT keyword.

SQL statement

SELECT DISTINCT(FirstName) FROM Individual;

Source Table

IndividualId	FirstName	LastName	UserName
1	Fred	Flinstone	freddo
2	Homer	Simpson	homey
3	Homer	Brown	notsofamous
4	Ozzy	Ozzbourne	sabbath
5	Homer	Gain	noplacelike

Result

In this example, using the DISTINCT keyword, all customers with the same first name are treated as one. This results in only one entry for Homer (even though there are three different entries in total).

FirstName
Fred
Homer
Ozzy